Solvent for acetyl cellulose.



UNITED STATES PATENT OFFICE.

WILLIAM G. LINDSAY, 0F CALIIWELL, NEW JERSEY, ASSIGNOR TO THE CELLULOIDCOMIANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

SOLVENT FOR AGETYL CELLULOSE.

No Drawing.

To all whomit may cum-crab lle it known that I, \Vnmuu G. LixnsAY, acitizen of the United States. residing in Caldwell, county of Essex.State of New Jersey. have invented certain new and use-- t'ulImprovements in Solvents for Acetyl Cellulose. of which the following isa specitication.

The various compositions to which the present invention relates areemployed in the arts, sometimes as imitations of natural substancesand-sometimes as films which are used 'for photographic purposes-as thebase upon which the sensitive coating is superimposed, Although thefinal or useful form'of'the different compounds of acetyl cellulose isthat of a solid or dry material, the different processesof conversioninto this final solid form involve. as is well understood, theemployment of solutions or mixtures of varying consistencies as to elasticity, stifi'ness. or fluidity, depending generally upon the proportionor kind of solvent used to the amount of the original baseacetylcellulose.

In the treatment of acetylcellulose for the production of flexible orplastic compounds I have discovered that Water, methyl alcohol andbenzol in admixture form a useful and very strong solvent for acetylcellulose of that variety which is freelv soluble in ace tone. Myinvention lies in the discovery that methyl alcohol, water, and benzol,when mixed in certain proportions, combine to produce a liquid which isa solvent for the described varietyof acetyl cellulose at ordinary orroom temperature, say 20 (3.. and that the use of this solvent undercertain conditions for the manufacture of acetyl cellulose plasticcompounds affords means of producing a material having great toughness,flexibility, and to a very large extent freedom from brittleness. Thequalities thus imparted to the finished material I have found furtherare of a permanent nature and that the product when thoroughly seasonedis well adapted for carving, molding, and polishing.

I have also discovered that this solvent may be employed for themanufacture of a non-inflammable plastic composition which will possesstoughness, flexibility. and freedom from brittleness .to a markeddegree, and this I have formed the subject of a separate application.

Specification of Letters Patent.

Patented May 15, 1917.

Application filed May 23, 1912. Serial No. 699,232.

It could not be foretold that a mixture of water, methyl alcohol andbenzol would when added to an acetyl cellulose of the variety describedproduce a gelatinatedmass,.

and again it could not be foretold that the addition. ofparaethyltoluolsulfonamid to this mixture would produce a ma$ whichcould be rolled. pressed. and molded; On the contrary, it would beexpected that a mixture of water-and methyl alcohol with benzol wouldyield upon evaporation a residue high in benzol and water and would beuseless as a solvent for acetyl cellulose. As a matter of fact. however.I have not only discovered that the watcr-benzol-methy] alcohol mixturein certain proportions is a solvent for acetyl cellulose in the cold. orat.

ordinary room temperature. but that such a.

mixture when used with the acetyl cellulose described and certainsubstances such as paraethyltoluolsulfona mid evaporates subslantiallyunchanged with very little, if any, diminutionin its solventaction,:-that is, whatever change (if any) takes place in thecomposition of the mixed solvent during evaporatiomfits use as a solventin the manufacture of acetyl cellulose plastics is not impaired.

In order to carry out my invention a good example of the process to bepursued is as follows: To 100 parts of acetyl cellulose of the varietydescribed I add from 50 to 100 parts of a mixture composed of from 54 to61 parts. by weight. of the so-called commercial C. P. benzol and 46 to39 parts. by weight. of a methyl alcohol of a strength of from 93% to96.5,Z-. Other proportions will produce gelatinization, but theseproportions work best with paraethyltoluolsulfonamid. At ordinary roomtemperature there results a more or less gelatinous mass depending uponthe amount of solvents used. in which the particles of acetyl cellulosein a. comparatively short time become completely agglomerated oramalgamated, losing their original shape and coalescing without theaction of either heat or pressure. To the gelatinated mass thus producedI add from 30 to 50 parts of paraethyltoliiolsulfonamid-- the larger theproportion the more flexible and plastic (under heat) will be the finalmaterialand by the aid of a malaxator or other suitable kneading machineI obtain a uniform mixture. The mass thus produced is further worked upaccording to the wellknown processes for making nitro-celluloseparts byweight of methyl alcohol, and a camphor compounds. water. said methylalcohol being diluted to 10 Having thus described my invention, whatcontain about 3?; to 7 per cent. of water. I claim is,: 5 The combinedsolvent for acetyl cellulose WILLIAM LINDS of that variety which isfreely soluble in Witnesses: acetone comprising a mixture of about 54 toRUTH MEYERSON, 61 parts by weight of benzol about 46 to 39 J. E. HINDONHYDE.

floplel of this potent may be obtained 101 Me cents each, by addressingthe "-commiuionerot Patent.

wumnfton, D. 0.

